Kinetic Theory of Matter - The theory that states that all matter is made of small particles that are in random motion and that have space between them
Law of Conservation of Matter - A natural law of science that states that matter cannot be created or destroyed. Matter cannot just appear or disappear, it can only change its form.
Law of Superposition - one of the principles of geology scientists use to determine the relative ages of rock layers. This principle states that layers of rock are superimposed, or laid down one on top of another. The oldest rock strata will be on the bottom and the youngest at the top.
Lipids - An organic compound made up mostly of carbon, hydrogen and oxygen that is used as a long-term energy source. They are found in fats, oils and waxes and are insoluble in water.
Liquid - A state of matter in which the substance has a definite volume, but takes the shape of its container. Its particles move around each other freely.
Low Pressure - An area of atmospheric pressure that is lower than its surrounding environment. Low-pressure systems are associated with unsettled weather, including clouds, precipitation, and sometimes storms.
Low Tide - The lowest point the ocean level will fall to at a particular place during the day.
Lunar cycle - The regular, repeating pattern of the appearance of the face of the Moon as it revolves around the Earth.
Lunar eclipse- When the Earth passes between the Sun and the Moon, blocking the light reflected off the Moon